JP2868366B2 - Back screen display method and apparatus using on-screen signal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video processing system, and more particularly to a method and apparatus for displaying a back screen using an on-screen signal when there is no signal.

[0002]

2. Description of the Related Art Currently, video processing systems such as color television receivers and video tape recorders have a blue back screen function to prevent noise from appearing on the screen when there is no video signal input. The blue back screen is for processing a screen in blue.

FIG. 1 is a block diagram showing a conventional blue back screen display. Reference numeral 10 denotes a color signal processing unit which reproduces an input video signal to reproduce red (hereinafter referred to as R).
), Green (hereinafter, referred to as G), and blue (hereinafter, referred to as B) primary color signals, and at the same time, the discrimination signal (DE
T) and horizontal and vertical synchronization signals (Hs, Vs).
The color signal processing unit (10) generally uses a one-chip general-purpose color signal processing IC. For example, a Philips TDA8362 may be used.

The discrimination signal (DET) is a signal indicating whether or not a video signal is input, and is a horizontal synchronizing signal (H) of the video signal.
When a video signal is input by detection of the presence or absence of s), the signal is output to "low", and when no signal is output, it is output to "high". The horizontal and vertical synchronizing signals (Hs, Vs) are signals respectively synchronized with the horizontal and vertical synchronizing signals of the input video signal when a video signal is input, and internally oscillated signals when there is no signal. Is output to

Reference numeral 20 denotes a microcomputer which controls the entire system, and generates a blue back screen drive signal (Bon) for blue back screen processing when the discrimination signal (DET) is input and there is no signal. The microcomputer (20) also generates an on-screen signal (Son) for displaying characters on the screen. Reference numeral 40 denotes a blue back screen circuit, which is a blue back screen drive signal (B
on) to display a blue screen.

Reference numeral 30 denotes a picture tube driving unit, which drives a picture tube (CRT) by the primary color signals (R, G, B) of the color signal processing unit (10) so that a screen is displayed. At the time of signal, the picture tube (CRT) is driven by the output of the blue back screen circuit (40) instead of the absence of the input of the primary color signals (R, G, B) to display a blue screen. In addition, a picture tube (CRT) is driven by an on-screen signal (Son) of the microcomputer (20) to display characters on a screen.

[0007]

The conventional blue back screen display system as described above requires a blue back screen circuit for blue-white processing of the screen, so that the circuit is complicated and its components are required in large quantities. There was a problem. Therefore, an object of the present invention is to provide a video processing system,
An object of the present invention is to provide a method and apparatus for displaying a back screen using an on-screen signal for displaying an existing character without using a separate back screen circuit.

[0008]

The present invention relates to a video processing system comprising a color signal processing unit (10), a microcomputer (20), and a picture tube driving unit (30) for driving a picture tube (CRT). a signal input inspection process for inspecting the presence or absence of the video signal input by the discrimination signal input, when no signal is sometimes determined, raw extended on-screen signal for displaying a predetermined color which is set in advance on the entire screen from the on-screen signal
A back screen display process of displaying the back screen was formed, and a back screen release process the back video signals during the performance of the screen display process by blocking the extended on-screen signal generator and the input to cancel the back screen A back screen display method using an on-screen signal is provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. Figure 2 is a block diagram to which the present invention is applied,
Picture tube CRT, color signal processing unit 10, microcomputer 20
And a picture tube driving unit 30. The configuration shown in FIG. 3 is obtained by removing the blue back screen circuit 40 in the configuration shown in FIG.

FIG. 3 is an operation waveform diagram of FIG. 2 of the present invention, wherein A shows the horizontal synchronizing signal Hs output from the color signal processing unit 10. B is an on-screen signal Son output from the microcomputer 20 and indicates that it is output during the character display period T within 1H (one horizontal scanning period). C is an extended on-screen signal Son 'output from the microcomputer 20, and is a horizontal synchronizing signal H
It is shown that output is performed over the entire 1H in synchronization with s.

FIG. 4 is a flow chart according to the present invention. The signal input inspection step for inspecting the presence / absence of a video signal based on the discrimination signal input, and the extension ON when it is determined that there is no signal in the signal input inspection step. A back screen displaying step of generating a screen signal and displaying a back screen; and a back screen for interrupting generation of an extended on-screen signal and stopping the back screen when an image signal during the back screen displaying step is input. Release process.

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. First, the function and operation of the color signal processing unit 10 in FIG. 2 are the same as those in FIG. 1 described above, and thus detailed description will be omitted. The picture tube driving unit 30 drives the picture tube CRT by the primary color signals R, G, B output from the color signal processing unit 10 in response to the input of the video signal, and
The display of characters by the on-screen signal Son of 0 is the same as that described above.

The on-screen signal Son for displaying the character is output during the character display period T within 1H of the horizontal synchronization signal Hs in FIG. 3A as shown in FIG. 3B. At this time, the picture tube driving unit 30 operates in the character display period T.
During the period, the picture tube CRT is driven by the on-screen signal Son instead of the primary color signals R, G, B of the color signal processing unit 10 to display characters.

On the other hand, when there is no signal, the extended on-screen signal Son 'output for processing the back screen by the microcomputer 20 according to the discrimination signal DET is synchronized with the horizontal synchronizing signal Hs as shown in FIG. Is output over In such a case, the picture tube driving section 30 receives a picture tube CRT by the extended on-screen signal Son '.
Of the cathode of each of the R, G, and B cathode colors.

The above operation will be described with reference to the flowchart of FIG.
In step (A1) of FIG. 4, whether the determination signal DET input from the color signal processing unit 10 is "high" is checked to determine whether a video signal is input. When the discrimination signal DET is input "high", there is no signal, so that in step (A2), a 1H extended on-screen signal Son 'as shown in FIG. 30 to process the back screen to the set color in R, G, B. At this time, the extended on-screen signal S
On 'is generated in synchronization with the horizontal and vertical synchronizing signals Hs and Vs oscillated from the color signal processing unit 10, thereby synchronizing with horizontal and vertical scanning of the picture tube CRT. Each time the generation of the 1H extended on-screen Son 'is completed, the determination signal (DET) is previously set to "high" in step (A3).
(A2)
The steps are repeatedly performed, and when it becomes "low", it is determined that a video signal is input, and the step (A4) is performed. In the step (A4), the extended on-screen signal So
The screen according to the input video signal is displayed by cutting off the occurrence of n ′ and canceling the back screen processing.

On the other hand, the setting of the hue for the back screen processing as described above is performed such that the extended on-screen signal Son 'is applied to one of the R, G, and B cathodes of the picture tube CRT by the picture tube driving unit 30. This is performed by setting in advance. Here, a desired hue can be easily displayed by a combination of the R, G, and B colors.

[0017]

As described above, the present invention does not use a separate back screen circuit for displaying a back screen in an image processing system, but simply uses an on-screen signal for displaying existing characters. As a method of displaying a back screen, there is an advantage that cost can be reduced and its reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a related art.

FIG. 2 is a block diagram to which the present invention is applied;

FIG. 3 is an operation waveform diagram of FIG. 2;

FIG. 4 is a flowchart according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 color signal processing unit 20 microcomputer 30 picture tube driving unit CRT picture tube

Claims (11)

(57) [Claims] A color signal processing unit for detecting an input video signal, generating a discrimination signal, and generating horizontal and vertical synchronization signals;
A microcomputer (20) for controlling the back screen display by inputting the discrimination signal and the horizontal and vertical synchronization signals, and an extended on-screen signal under the control of the microcomputer (20).
Signal to the R, G, B cathode of the picture tube (CRT)
A method for back-screen display using an on-screen signal of a picture processing system having a picture tube driving unit (30) driven as above, wherein a signal input inspection step of inspecting the presence or absence of a video signal input according to the discrimination signal input; when no signal sometimes determined by the signal input testing process, to display the back screen extended on-screen signal indicating the predetermined color that has been set pre Me on the entire screen generated <br/> to from the on-screen signal A back screen displaying step; and a back screen releasing step of stopping generation of the extended on-screen signal and stopping display of the back screen when a video signal is input during the execution of the back screen displaying step. Back screen display method using an on-screen signal. 2. The method according to claim 1, wherein the signal input checking step checks the discrimination signal every one horizontal scanning period, and the back screen displaying step or the back screen releasing step is executed every one horizontal scanning period. A back screen display method using the on-screen signal according to claim 1. 3. The method according to claim 1, wherein the extended on-screen signal is a signal synchronized with the horizontal and vertical synchronization signals. 4. The on-screen display according to claim 1, wherein the back-screen display hue in the back-screen display process is set by selecting and applying an extended on-screen signal corresponding to primary color signal driving of the picture tube driving unit. Back screen display method using signals. 5. A back screen display device using an on-screen signal of a video processing system, wherein a discrimination signal is processed by processing an input video signal, a color signal processing means for generating horizontal and vertical synchronization signals, A predetermined color set in advance according to the entire screen
Wherein the extended on-screen signal to be displayed on the body Onsukuri
Control means for controlling the back screen by generating the extended on-screen signal from the R, G, B camera of the picture tube.
And a picture tube driving unit for driving the liquid crystal to apply a voltage to the display screen. 6. The back screen display device according to claim 5, wherein said color signal processing means further comprises a local oscillator for generating said horizontal and vertical synchronization signals when there is no signal. 7. The back screen display device according to claim 5, wherein said control means further comprises means for extending a pulse width of said on-screen signal as one horizontal scanning period when there is no signal. 8. A back screen display method using an on-screen signal of an image processing system, wherein a determination signal corresponding to an input of an image signal, a horizontal and vertical synchronization signal, and a primary color signal of red, green, and yellow are generated. A first step, an on-screen signal including character information according to the discrimination signal, or an on-screen signal generated based on the on-screen signal.
A second step of selectively generating an extended on-screen signal for displaying a predetermined color set in advance on the entire screen; and displaying characters by the on-screen signal, or a back screen by the extended on-screen signal. a third step of driving R kinescope, G, and B cathode to display, and a fourth step of blocking the extension on-screen when a video signal is input during the display of the back sCREEN A back screen display method characterized by the above-mentioned. 9. The second step includes generating the extended on-screen signal during one horizontal scanning period when there is no signal, and when the video signal is not input during the next horizontal scanning period, the extended on-screen signal is generated. 9. The method according to claim 8, wherein the extended on-screen signal is interrupted when a video signal is input. 10. The back screen display method according to claim 8, wherein said extended on-screen signal is synchronized with horizontal and vertical synchronization signals generated by said color signal processing means. 11. the back screen color, said extended on-screen image receiving tube R, G, either by connecting to one with B in the cathode, or the R, G, B cathode of a predetermined combination 9. The method according to claim 8, wherein the method is selectively determined by the following.